Webb Simpson recorded a superb course record-equalling round of 9-under-par 63 to establish a five-shot halfway lead in The Players Championship at TPC Sawgrass.
The 32-year-old American was an astonishing 11-under-par for his round through 16 holes, draining one eagle and nine birdies to grab a seven-shot lead, before he found water at the island green of the par-3 17th hole.
I don't think any lead is safe.Webb Simpson
He eventually made a double bogey-5, but his par at the final hole was still enough to make the record books and set an imposing 36-hole total of 15-under 129.
"You're as focussed as can be," he said afterwards. "But at some point you're just kind of laughing. Everything was going in. Just a very fun day.
"It's rare as a golfer when everything is working well. Driving, iron play, chipping and putting, today everything came together. But 15-under through two days here, which is a lot lower than I ever would have expected to be."
Indeed, his success is all the more surprising because he has a poor record in the event, six times failing to make the top 65 and never once finishing inside the top ten in eight visits.
"I think it's a beautiful golf course in the sense that I could go shoot a few under tomorrow because there's birdie holes out there," he said. "But if you're off a little bit, you make bogeys or double bogeys as easy as you can make birdies. I don't think any lead is safe."
Simpson's lead is the largest 36-hole advantage in the history of the tournament, however Alex Cejka did blow a five-shot lead after 54 holes in 2009.
He will be chased over the weekend by Charl Schwartzel, Danny Lee and Patrick Cantlay, who are all at 10-under 134. Chesson Hadley, Alex Noren and Charles Howell II are a shot further back on 9-under par.
Perhaps the biggest danger to Simpson is 2016 winner Jason Day, who blasted a 66 to reach 8-under after 36 holes.
Simpson is 1/250 to complete the victory, while Day is 500/1, Cantlay 2000/1 and Noren 750/1.
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